Reading disability (RD) is a serious, life-long condition that negatively affects schooling, employment, health status, and social adjustment. With the traditional approach for identifying RD, IQ-achievement discrepancy, students repeatedly fail before they qualify as RD. During this waiting period, which often extends to 4th or 5th grade, opportunity for intervention is lost, making remediation difficult. Therefore, the 2004 reauthorization of the Individuals with Disabilities Education Improvement Act permits states to discontinue use of IQ- achievement discrepancy in favor of a response-to-intervention (RTI) approach to RD identification. RTI is a promising method for the prevention and early identification of RD, but important questions remain unanswered. This project involves 750 low-study-entry, 170 average-study-entry, and 84 high-study-entry students who enter the study in 1st grade. To all students, we administer static assessments, dynamic assessment, and ongoing progress monitoring in fall of 1st grade, and we administer an assessment battery in spring of grades 1-4. We constitute a representative sample to include all average- and high-study-entry students plus a subsample of 84 low-study-entry students. With this representative sample, we consider how multi-method screening approaches, conducted in fall of 1st grade, enhance the predictive utility of long-term risk designations. We randomly assign the 750 low-study-entry students to no treatment control or 1 of 2 treatments (decoding/fluency vs. decoding/fluency/comprehension). With these low-study-entry students, we (a) assess how the nature of 1st-grade intervention affects reading outcomes and examine how initial child characteristics interact with intervention in moderating outcomes; (b) assess how the nature of intervention affects the prevalence of RD subtypes, with and without ADHD, and explore the prevalence of those subtypes; and (c) evaluate RTI as a 1st-grade classification and prevention model against an external criterion for RD. PUBLIC HEALTH RELEVANCE Reading disability (RD) is a serious, life-long condition that negatively affects the schooling, employment, health status, and social adjustment, creating a public health problem for society. Responsive-to-intervention (RTI) is a promising method for preventing and identifying RD, but important questions remain unanswered. We address unanswered questions by assessing how multi-method screening improves decision utility for designating RD risk at beginning of 1st grade; exploring the value of 1st-grade comprehension intervention in prevention RD; considering RD subtypes; and externally evaluating RTI as a 1st-grade RD identification and prevention system.